

PUTREFACTIVE FERMENTATIONS IN THE INTESTINE. 185 



this is not found in any part of the alimentary tract, the oxygen 

 soon being absorbed and the nitrogen left, while a quantity of 

 carbonic anhydride and hydrogen from the fermentation of the 

 sugar are set free, lactic and butyric acids being produced at the 

 same time. 



Indol and skatol are also formed by putrefactive fermentation 

 of the leucin and tyrosin, although this is in a great measure 

 held in check by the antiseptic nature of the bile. 



It is in the large intestine that putrefactive fermentations have 

 the greatest effect, the acid reaction being caused by the various 

 acids produced. 



With regard to the interesting question, Why do not the di- 

 gestive fluids dissolve the tissues of the organs in which they are 

 contained, we cannot speak positively. We cannot now say that 

 the "vital principle" has a protective influence, for we know the 

 fact that a tissue being alive is not sufficient to ward off the diges- 

 tive action of the alimentary juices, since the limb of a living frog 

 is digested when introduced through a fistula into the stomach of 

 a dog; and when the intestinal juice trickles from a fistula the 

 neighboring skin, the snout, and the tongue of the animal soon 

 become eaten away owing to its licking the fluid, which rapidly 

 digests these parts so as to destroy the skin and even expose the 

 bloodvessels. 



We can however modify John Hunter's statement that the 

 resisting power was associated with the life of the structures, by 

 saying that it is not the property of an abstract "vital principle" 

 but a special resisting power dependent upon the specific character 

 of the vital processes of certain textures. 



16 



